Unless otherwise indicated herein, approaches described in this section are not prior art to the claims listed below and are not admitted to be prior art by inclusion in this section.
With the growing popularity of portable devices and wearable devices, more and more different types of sensors and auxiliary devices are available for portable and wearable devices on the market. Typically a portable or wearable device is equipped with one or more Universal Serial Bus (USB) connectors through which one or more sensors and/or auxiliary devices can interface and connect to the portable or wearable device. However, to enable the use of a conventional USB connector, an additional integrated-circuit (IC) chip is often required to connect a differential data pair of the conventional USB connector, namely the data plus/data minus (DP/DM) differential lines, to an Inter-Integrated Circuit (I2C) bus of the portable or wearable device. The requirement of the additional IC chip adds cost, which is undesirable. Moreover, when debugging through a conventional USB connector, a USB switch is often required to convert the USB DP/DM signals to universal asynchronous receiver/transmitter (UART) transmit (TX) and receive (RX) signals. The requirement of the USB switch adds cost and downgrades signal quality, which is also undesirable. Furthermore, although some portable and wearable devices may have built-in sensor(s), lower-end portable and wearable devices may not be equipped with sensors such as pressure sensor, hygrometer, gas detector or ultraviolet (UV) sensor.